Outlook unable to connect and sync with exchange server

You may need to modify your HOSTS file to include an entry that maps to the Exchange server.  I would try this first and see if it fixes it.  If not, there are other things you can try.

Can you give me an example of the HOSTS file entry?

just put the IP address of the Exchange server, then press TAB, then enter the host name of the Exchange server.  Then save the file.  Make sure it doesn't add .txt to the end of the file--the HOSTS file should have no file extension.

While HOSTS file will work, it is a poor answer. You should avoid using HOSTS file where possible. People forget they are there and then when something changes find that things do not work. I have inherited two networks with hosts files and removed them all, and deployed four networks using the Cisco VPN client (including my home network) and was able to use Outlook over all of them. Hosts files are not required.

Does name resolution work for the Exchange server over the VPN connection? Try and ping the Exchange server by all three combinations of IP address, netbios and FQDN. It should resolve to the internal IP address. If it comes back with an external address then name resolution isn't working correctly.

If it is only one user then it has to be something with their specific machine. Is it location dependant?

Simon.

I will have the user try pinging as you suggested.  Not sure what you mean by location dependant.  The user is part of the domain that the Excahnge server is on.  It is a small network of 25 users.

By location dependant I mean if the user goes somewhere else with their VPN connection, does it work in a different location?

Simon.

He has had problems from at least 3 different locations.  He has tried from home, hotel and wireless air card.  All three pings timed out.  I am sending him a new VPN profile file.

the HOSTS file method is not a permanent fix (unless you want it to be) but it is a quick and easy way to help narrow down where the problem is occuring.  At least if the HOSTS file works, then you know it is a DNS resolution issue.

Here is the result of an IPCONFIG from the users computer.  Could the Microsoft Loopback Adaptor be causing the problem?  

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.
C:\Documents and Settings\jcameron>Ipconfig /all
Windows IP Configuration
        Host Name . . . . . . . . . . . . : jim
        Primary Dns Suffix  . . . . . . . :
        Node Type . . . . . . . . . . . . : Hybrid
        IP Routing Enabled. . . . . . . . : No
        WINS Proxy Enabled. . . . . . . . : No
        DNS Suffix Search List. . . . . . :
Ethernet adapter Local Area Connection 6:
        Connection-specific DNS Suffix  . :
        Description . . . . . . . . . . . : Microsoft Loopback Adapter
        Physical Address. . . . . . . . . :
        Dhcp Enabled. . . . . . . . . . . : No
        IP Address. . . . . . . . . . . . : 10.10.0.10
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . . . . :
Ethernet adapter Local Area Connection 2:
        Media State . . . . . . . . . . . : Media disconnected
        Description . . . . . . . . . . . : Intel(R) 82567LM Gigabit Network Con
nection
        Physical Address. . . . . . . . . :
Ethernet adapter Local Area Connection 5:
        Connection-specific DNS Suffix  . :
        Description . . . . . . . . . . . : Novatel Wireless Ovation EV-DO Netwo
rk Adapter
        Physical Address. . . . . . . . . :
        Dhcp Enabled. . . . . . . . . . . : Yes
        Autoconfiguration Enabled . . . . : Yes
        IP Address. . . . . . . . . . . . : 75.220.91.187
        Subnet Mask . . . . . . . . . . . : 255.0.0.0
        Default Gateway . . . . . . . . . : 75.220.91.1
        DHCP Server . . . . . . . . . . . : 75.220.91.1
        DNS Servers . . . . . . . . . . . : 66.174.95.44
                                            66.174.92.14
        Lease Obtained. . . . . . . . . . : Wednesday, April 22, 2009 3:59:04 PM
        Lease Expires . . . . . . . . . . : Saturday, April 25, 2009 3:59:04 PM
Ethernet adapter Local Area Connection 3:
        Connection-specific DNS Suffix  . :
        Description . . . . . . . . . . . : Cisco Systems VPN Adapter
        Physical Address. . . . . . . . . :
        Dhcp Enabled. . . . . . . . . . . : No
        IP Address. . . . . . . . . . . . : 192.168.248.144
        Subnet Mask . . . . . . . . . . . : 255.255.255.0
        Default Gateway . . . . . . . . . :
        DNS Servers . . . . . . . . . . . : 192.168.248.10
        Primary WINS Server . . . . . . . : 192.168.248.10
C:\Documents and Settings\jcameron>